src/x64/code-stubs-x64.h

   1 // Copyright 2011 the V8 project authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef V8_X64_CODE_STUBS_X64_H_
   6 #define V8_X64_CODE_STUBS_X64_H_
   7
   8 #include "src/code-stubs.h"
   9
  10 namespace v8 {
  11 namespace internal {
  12
  13
  14 void ArrayNativeCode(MacroAssembler* masm, Label* call_generic_code);
  15
  16 class StoreBufferOverflowStub: public PlatformCodeStub {
  17  public:
  18   StoreBufferOverflowStub(Isolate* isolate, SaveFPRegsMode save_fp)
  19       : PlatformCodeStub(isolate), save_doubles_(save_fp) { }
  20
  21   void Generate(MacroAssembler* masm);
  22
  23   static void GenerateFixedRegStubsAheadOfTime(Isolate* isolate);
  24   virtual bool SometimesSetsUpAFrame() { return false; }
  25
  26  private:
  27   SaveFPRegsMode save_doubles_;
  28
  29   Major MajorKey() const { return StoreBufferOverflow; }
  30   int MinorKey() const { return (save_doubles_ == kSaveFPRegs) ? 1 : 0; }
  31 };
  32
  33
  34 class StringHelper : public AllStatic {
  35  public:
  36   // Generate code for copying characters using the rep movs instruction.
  37   // Copies rcx characters from rsi to rdi. Copying of overlapping regions is
  38   // not supported.
  39   static void GenerateCopyCharacters(MacroAssembler* masm,
  40                                      Register dest,
  41                                      Register src,
  42                                      Register count,
  43                                      String::Encoding encoding);
  44
  45
  46   // Generate string hash.
  47   static void GenerateHashInit(MacroAssembler* masm,
  48                                Register hash,
  49                                Register character,
  50                                Register scratch);
  51   static void GenerateHashAddCharacter(MacroAssembler* masm,
  52                                        Register hash,
  53                                        Register character,
  54                                        Register scratch);
  55   static void GenerateHashGetHash(MacroAssembler* masm,
  56                                   Register hash,
  57                                   Register scratch);
  58
  59  private:
  60   DISALLOW_IMPLICIT_CONSTRUCTORS(StringHelper);
  61 };
  62
  63
  64 class SubStringStub: public PlatformCodeStub {
  65  public:
  66   explicit SubStringStub(Isolate* isolate) : PlatformCodeStub(isolate) {}
  67
  68  private:
  69   Major MajorKey() const { return SubString; }
  70   int MinorKey() const { return 0; }
  71
  72   void Generate(MacroAssembler* masm);
  73 };
  74
  75
  76 class StringCompareStub: public PlatformCodeStub {
  77  public:
  78   explicit StringCompareStub(Isolate* isolate) : PlatformCodeStub(isolate) {}
  79
  80   // Compares two flat ASCII strings and returns result in rax.
  81   static void GenerateCompareFlatAsciiStrings(MacroAssembler* masm,
  82                                               Register left,
  83                                               Register right,
  84                                               Register scratch1,
  85                                               Register scratch2,
  86                                               Register scratch3,
  87                                               Register scratch4);
  88
  89   // Compares two flat ASCII strings for equality and returns result
  90   // in rax.
  91   static void GenerateFlatAsciiStringEquals(MacroAssembler* masm,
  92                                             Register left,
  93                                             Register right,
  94                                             Register scratch1,
  95                                             Register scratch2);
  96
  97  private:
  98   virtual Major MajorKey() const { return StringCompare; }
  99   virtual int MinorKey() const { return 0; }
 100   virtual void Generate(MacroAssembler* masm);
 101
 102   static void GenerateAsciiCharsCompareLoop(
 103       MacroAssembler* masm,
 104       Register left,
 105       Register right,
 106       Register length,
 107       Register scratch,
 108       Label* chars_not_equal,
 109       Label::Distance near_jump = Label::kFar);
 110 };
 111
 112
 113 class NameDictionaryLookupStub: public PlatformCodeStub {
 114  public:
 115   enum LookupMode { POSITIVE_LOOKUP, NEGATIVE_LOOKUP };
 116
 117   NameDictionaryLookupStub(Isolate* isolate,
 118                            Register dictionary,
 119                            Register result,
 120                            Register index,
 121                            LookupMode mode)
 122       : PlatformCodeStub(isolate),
 123         dictionary_(dictionary),
 124         result_(result),
 125         index_(index),
 126         mode_(mode) { }
 127
 128   void Generate(MacroAssembler* masm);
 129
 130   static void GenerateNegativeLookup(MacroAssembler* masm,
 131                                      Label* miss,
 132                                      Label* done,
 133                                      Register properties,
 134                                      Handle<Name> name,
 135                                      Register r0);
 136
 137   static void GeneratePositiveLookup(MacroAssembler* masm,
 138                                      Label* miss,
 139                                      Label* done,
 140                                      Register elements,
 141                                      Register name,
 142                                      Register r0,
 143                                      Register r1);
 144
 145   virtual bool SometimesSetsUpAFrame() { return false; }
 146
 147  private:
 148   static const int kInlinedProbes = 4;
 149   static const int kTotalProbes = 20;
 150
 151   static const int kCapacityOffset =
 152       NameDictionary::kHeaderSize +
 153       NameDictionary::kCapacityIndex * kPointerSize;
 154
 155   static const int kElementsStartOffset =
 156       NameDictionary::kHeaderSize +
 157       NameDictionary::kElementsStartIndex * kPointerSize;
 158
 159   Major MajorKey() const { return NameDictionaryLookup; }
 160
 161   int MinorKey() const {
 162     return DictionaryBits::encode(dictionary_.code()) |
 163         ResultBits::encode(result_.code()) |
 164         IndexBits::encode(index_.code()) |
 165         LookupModeBits::encode(mode_);
 166   }
 167
 168   class DictionaryBits: public BitField<int, 0, 4> {};
 169   class ResultBits: public BitField<int, 4, 4> {};
 170   class IndexBits: public BitField<int, 8, 4> {};
 171   class LookupModeBits: public BitField<LookupMode, 12, 1> {};
 172
 173   Register dictionary_;
 174   Register result_;
 175   Register index_;
 176   LookupMode mode_;
 177 };
 178
 179
 180 class RecordWriteStub: public PlatformCodeStub {
 181  public:
 182   RecordWriteStub(Isolate* isolate,
 183                   Register object,
 184                   Register value,
 185                   Register address,
 186                   RememberedSetAction remembered_set_action,
 187                   SaveFPRegsMode fp_mode)
 188       : PlatformCodeStub(isolate),
 189         object_(object),
 190         value_(value),
 191         address_(address),
 192         remembered_set_action_(remembered_set_action),
 193         save_fp_regs_mode_(fp_mode),
 194         regs_(object,   // An input reg.
 195               address,  // An input reg.
 196               value) {  // One scratch reg.
 197   }
 198
 199   enum Mode {
 200     STORE_BUFFER_ONLY,
 201     INCREMENTAL,
 202     INCREMENTAL_COMPACTION
 203   };
 204
 205   virtual bool SometimesSetsUpAFrame() { return false; }
 206
 207   static const byte kTwoByteNopInstruction = 0x3c;  // Cmpb al, #imm8.
 208   static const byte kTwoByteJumpInstruction = 0xeb;  // Jmp #imm8.
 209
 210   static const byte kFiveByteNopInstruction = 0x3d;  // Cmpl eax, #imm32.
 211   static const byte kFiveByteJumpInstruction = 0xe9;  // Jmp #imm32.
 212
 213   static Mode GetMode(Code* stub) {
 214     byte first_instruction = stub->instruction_start()[0];
 215     byte second_instruction = stub->instruction_start()[2];
 216
 217     if (first_instruction == kTwoByteJumpInstruction) {
 218       return INCREMENTAL;
 219     }
 220
 221     DCHECK(first_instruction == kTwoByteNopInstruction);
 222
 223     if (second_instruction == kFiveByteJumpInstruction) {
 224       return INCREMENTAL_COMPACTION;
 225     }
 226
 227     DCHECK(second_instruction == kFiveByteNopInstruction);
 228
 229     return STORE_BUFFER_ONLY;
 230   }
 231
 232   static void Patch(Code* stub, Mode mode) {
 233     switch (mode) {
 234       case STORE_BUFFER_ONLY:
 235         DCHECK(GetMode(stub) == INCREMENTAL ||
 236                GetMode(stub) == INCREMENTAL_COMPACTION);
 237         stub->instruction_start()[0] = kTwoByteNopInstruction;
 238         stub->instruction_start()[2] = kFiveByteNopInstruction;
 239         break;
 240       case INCREMENTAL:
 241         DCHECK(GetMode(stub) == STORE_BUFFER_ONLY);
 242         stub->instruction_start()[0] = kTwoByteJumpInstruction;
 243         break;
 244       case INCREMENTAL_COMPACTION:
 245         DCHECK(GetMode(stub) == STORE_BUFFER_ONLY);
 246         stub->instruction_start()[0] = kTwoByteNopInstruction;
 247         stub->instruction_start()[2] = kFiveByteJumpInstruction;
 248         break;
 249     }
 250     DCHECK(GetMode(stub) == mode);
 251     CpuFeatures::FlushICache(stub->instruction_start(), 7);
 252   }
 253
 254  private:
 255   // This is a helper class for freeing up 3 scratch registers, where the third
 256   // is always rcx (needed for shift operations).  The input is two registers
 257   // that must be preserved and one scratch register provided by the caller.
 258   class RegisterAllocation {
 259    public:
 260     RegisterAllocation(Register object,
 261                        Register address,
 262                        Register scratch0)
 263         : object_orig_(object),
 264           address_orig_(address),
 265           scratch0_orig_(scratch0),
 266           object_(object),
 267           address_(address),
 268           scratch0_(scratch0) {
 269       DCHECK(!AreAliased(scratch0, object, address, no_reg));
 270       scratch1_ = GetRegThatIsNotRcxOr(object_, address_, scratch0_);
 271       if (scratch0.is(rcx)) {
 272         scratch0_ = GetRegThatIsNotRcxOr(object_, address_, scratch1_);
 273       }
 274       if (object.is(rcx)) {
 275         object_ = GetRegThatIsNotRcxOr(address_, scratch0_, scratch1_);
 276       }
 277       if (address.is(rcx)) {
 278         address_ = GetRegThatIsNotRcxOr(object_, scratch0_, scratch1_);
 279       }
 280       DCHECK(!AreAliased(scratch0_, object_, address_, rcx));
 281     }
 282
 283     void Save(MacroAssembler* masm) {
 284       DCHECK(!address_orig_.is(object_));
 285       DCHECK(object_.is(object_orig_) || address_.is(address_orig_));
 286       DCHECK(!AreAliased(object_, address_, scratch1_, scratch0_));
 287       DCHECK(!AreAliased(object_orig_, address_, scratch1_, scratch0_));
 288       DCHECK(!AreAliased(object_, address_orig_, scratch1_, scratch0_));
 289       // We don't have to save scratch0_orig_ because it was given to us as
 290       // a scratch register.  But if we had to switch to a different reg then
 291       // we should save the new scratch0_.
 292       if (!scratch0_.is(scratch0_orig_)) masm->Push(scratch0_);
 293       if (!rcx.is(scratch0_orig_) &&
 294           !rcx.is(object_orig_) &&
 295           !rcx.is(address_orig_)) {
 296         masm->Push(rcx);
 297       }
 298       masm->Push(scratch1_);
 299       if (!address_.is(address_orig_)) {
 300         masm->Push(address_);
 301         masm->movp(address_, address_orig_);
 302       }
 303       if (!object_.is(object_orig_)) {
 304         masm->Push(object_);
 305         masm->movp(object_, object_orig_);
 306       }
 307     }
 308
 309     void Restore(MacroAssembler* masm) {
 310       // These will have been preserved the entire time, so we just need to move
 311       // them back.  Only in one case is the orig_ reg different from the plain
 312       // one, since only one of them can alias with rcx.
 313       if (!object_.is(object_orig_)) {
 314         masm->movp(object_orig_, object_);
 315         masm->Pop(object_);
 316       }
 317       if (!address_.is(address_orig_)) {
 318         masm->movp(address_orig_, address_);
 319         masm->Pop(address_);
 320       }
 321       masm->Pop(scratch1_);
 322       if (!rcx.is(scratch0_orig_) &&
 323           !rcx.is(object_orig_) &&
 324           !rcx.is(address_orig_)) {
 325         masm->Pop(rcx);
 326       }
 327       if (!scratch0_.is(scratch0_orig_)) masm->Pop(scratch0_);
 328     }
 329
 330     // If we have to call into C then we need to save and restore all caller-
 331     // saved registers that were not already preserved.
 332
 333     // The three scratch registers (incl. rcx) will be restored by other means
 334     // so we don't bother pushing them here.  Rbx, rbp and r12-15 are callee
 335     // save and don't need to be preserved.
 336     void SaveCallerSaveRegisters(MacroAssembler* masm, SaveFPRegsMode mode) {
 337       masm->PushCallerSaved(mode, scratch0_, scratch1_, rcx);
 338     }
 339
 340     inline void RestoreCallerSaveRegisters(MacroAssembler*masm,
 341                                            SaveFPRegsMode mode) {
 342       masm->PopCallerSaved(mode, scratch0_, scratch1_, rcx);
 343     }
 344
 345     inline Register object() { return object_; }
 346     inline Register address() { return address_; }
 347     inline Register scratch0() { return scratch0_; }
 348     inline Register scratch1() { return scratch1_; }
 349
 350    private:
 351     Register object_orig_;
 352     Register address_orig_;
 353     Register scratch0_orig_;
 354     Register object_;
 355     Register address_;
 356     Register scratch0_;
 357     Register scratch1_;
 358     // Third scratch register is always rcx.
 359
 360     Register GetRegThatIsNotRcxOr(Register r1,
 361                                   Register r2,
 362                                   Register r3) {
 363       for (int i = 0; i < Register::NumAllocatableRegisters(); i++) {
 364         Register candidate = Register::FromAllocationIndex(i);
 365         if (candidate.is(rcx)) continue;
 366         if (candidate.is(r1)) continue;
 367         if (candidate.is(r2)) continue;
 368         if (candidate.is(r3)) continue;
 369         return candidate;
 370       }
 371       UNREACHABLE();
 372       return no_reg;
 373     }
 374     friend class RecordWriteStub;
 375   };
 376
 377   enum OnNoNeedToInformIncrementalMarker {
 378     kReturnOnNoNeedToInformIncrementalMarker,
 379     kUpdateRememberedSetOnNoNeedToInformIncrementalMarker
 380   };
 381
 382   void Generate(MacroAssembler* masm);
 383   void GenerateIncremental(MacroAssembler* masm, Mode mode);
 384   void CheckNeedsToInformIncrementalMarker(
 385       MacroAssembler* masm,
 386       OnNoNeedToInformIncrementalMarker on_no_need,
 387       Mode mode);
 388   void InformIncrementalMarker(MacroAssembler* masm);
 389
 390   Major MajorKey() const { return RecordWrite; }
 391
 392   int MinorKey() const {
 393     return ObjectBits::encode(object_.code()) |
 394         ValueBits::encode(value_.code()) |
 395         AddressBits::encode(address_.code()) |
 396         RememberedSetActionBits::encode(remembered_set_action_) |
 397         SaveFPRegsModeBits::encode(save_fp_regs_mode_);
 398   }
 399
 400   void Activate(Code* code) {
 401     code->GetHeap()->incremental_marking()->ActivateGeneratedStub(code);
 402   }
 403
 404   class ObjectBits: public BitField<int, 0, 4> {};
 405   class ValueBits: public BitField<int, 4, 4> {};
 406   class AddressBits: public BitField<int, 8, 4> {};
 407   class RememberedSetActionBits: public BitField<RememberedSetAction, 12, 1> {};
 408   class SaveFPRegsModeBits: public BitField<SaveFPRegsMode, 13, 1> {};
 409
 410   Register object_;
 411   Register value_;
 412   Register address_;
 413   RememberedSetAction remembered_set_action_;
 414   SaveFPRegsMode save_fp_regs_mode_;
 415   Label slow_;
 416   RegisterAllocation regs_;
 417 };
 418
 419
 420 } }  // namespace v8::internal
 421
 422 #endif  // V8_X64_CODE_STUBS_X64_H_